Reactions of titanium or zirconium compounds with amino compounds are known. For example, Yoshino et al., in the Bulletin of The Chemical Society of Japan, Vol. 46, 2899 (1973), have reported their observations in respect of certain mixtures of titanium and zirconium esters with nitrogen-containing compounds. Boiling a mixture of Zr isopropoxide and glycine dissolved in ethanol for 22 hours gave a white precipitate which was stated to be 2,5-piperazinedione. Substituting DL-alpha-alaline in that mixture, gave a white precipitate which was said to be 3,6-dimethyl-2,5-piperazinedione. When a mixture of glycine and Ti isopropoxide in isopropanol, and mixtures of glycine and Ti n-butoxide in ethanol and isopropanol, were heated to boiling, the glycine did not dissolve completely, but after 20 hours, light brown powders were obtained which were stated to be 2,5-piperazinedione. Moreover, in U.S. Pat. No. 2,824,114, Bostwick disclosed compounds prepared by reacting an alkyl titanium or zirconium ester with a monohydric, dihydric, or trihydric monoamino or diamino alcohol, e.g., di-hydroxyethyl-ethylene diamine, and suggested using his compounds as dispersing agents and as surface active agents for hydrocarbons and waxes. Similarly Beacham et al., in U.S. Pat. No. 2,824,115, disclosed combining organo titanium and organo zirconium compounds with polyhydroxyalkyl alkylene polyamines, and suggested using their compounds as dispersing agents, additives to paint and varnish formulations to improve durability, agents for the treatment of wool and animal fibers, and in various textile and cosmetic applications.
The use of zirconium compounds as cross-linking agents is described by Kucera in U. K. patent application GB 2 108 122 A. Kucera disclosed reacting a zirconium alkoxide with a dialkanol amine or trialkanol amine, and suggested using the resulting compounds as cross-linking agents in hydraulic fracturing of subterranean formations. The production of oil and gas can be stimulated by the hydraulic fracturing technique, in which a fluid composition is introduced into an oil or gas well at a flow rate and pressure which create and/or extend a fracture into the oil- or gas-containing formation. The fluid composition usually carries a proppant (e.g., sand, bauxite, etc.) which is forced into the fracture by the fluid composition and prevents closure of the formation after the fluid pressure is released. Tiner et al., in U.S. Pat. No. 3,888,312, provide an example of the use of titanium-containing cross-linking agents in fluid or hydraulic fracturing. They disclosed hydraulic fracturing of subterranean formations using aqueous gels prepared from a solvatable polysaccharide which had been cross-linked with ammonium tetralactotitanate(IV) or bis(triethanolamine)bis(isopropyl)-titanium.
Recovery of oil from subterranean formations frequently involves displacing crude oil with a driving fluid, e.g., gas, water, brine, steam, polymer solution, foam, or micellar solution. Ideally, such techniques (commonly called flooding techniques) would provide a bank of oil of substantial depth being driven to a producing well; in practice, that frequently is not the case. Oil-bearing strata are usually heterogeneous, some parts of them being more permeable to a driving fluid than others. As a consequence, channeling frequently occurs so that the driving fluid flows preferentially through zones depleted of oil (so-called "thief" zones) rather than through those parts of the strata which contain sufficient oil to make oil-recovery operations profitable. High permeability zones can also cause undesirable loss of drilling fluids when a well (e.g., water, oil or waste disposal) is being drilled. Misplaced casing perforations or casing leaks are another cause of channeling of the driving fluid through zones of high permeability in the subterranean formations. In addition, casing leaks sometimes occur in the annular region above the injection or production packer, and need to be dealt with whether the leaks occur in high or low permeability zones.
Hanlon et al., in U.S. Pat. No. 4,460,751, disclose a cross-linking composition and the use of the compositions in a method for reducing permeability of subterranean formations to water. They disclose preparing the composition by mixing (1) water, (2) a Zr salt (oxychloride, acetate, tetrachloride, o-sulfate, carbonate), (3) an acid having the formula HO-C(=O)-CH(OH)-R wherein R is H or alkyl (1-3 C) and (4) a amine having the formula R.sup.1 N(R.sup.2)R.sup.3 wherein R.sup.1 is hydroxyalkyl (1-3 C), R.sup.2 is alkyl (1-3 C) or R.sup.1, and R.sup.3 is H or R.sup.2.
The products of the present invention provide advantages over those of the prior art. For example, the titanium- and zirconium-containing compositions of the present invention have extremely slow rates of cross-linking. They can therefore be used at high temperatures and/or at high pH and still effect crosslinking at acceptable rates. Thus, for example, they can be used in a well completion fluid which contains a high level of brine. Consequently, the compositions of the present invention can be used in hotter geologic formations, including those at greater depths in oil and gas wells. In addition, the compositions of the present invention are better suited as cross-linkers than are those of the prior art in cross-linked gels used in hydraulic fracturing fluids and for plugging leaks and selectively plugging permeable zones.